i have a DHLA 48 on a supposed fresh rebuild...the car will idle at a steady 800, but between 1kand 4k it has a horrible time running, it needs to be feathered up to whatever rpm, but it will stay at a constant rpm... for example.... to get to 2k, i have to feather it and apply very little fuel, but once i get it to 2k, i can keep it there easily..... around 2k i can very slowly increase throttle without having to feather, but if i floor it it immediately just quits and dies..... Once i get passed 4k it runs great again... any ideas on this?!??!?!?!?!!?!?!?!?!?!!?!?

oh yeah.... fuel pressure is set at 3 psi using a holley blue pump anf fpr....

 

Ok first get your fuel psi down to 2.5, 3 will overload the needle and cause it
to run rich. Your experiencing a badly adjusted idle circuit or accelerator pump
, thats why at about 4K it run great, your now running on the main jets mostly,
so they must be close to right.

Once you get the fuel pressure down to 2.5 psi you can adjust the idle mixture
and then the AP pump. Gently screw the idle mixture screws in all the way to their
stops and back them both out 2.5 turns. That may work but you may need some
adjustment to get rid of the stumble (or minimize it anyway). Only adjust these
when the car is really good and hot. Do it a half turn at a time (in ot out). Adjust
both identically for now. What your aiming for is the leanest mixture that works
smoothly. Screwing the screws in leans the mixture and screwing them out makes
it richer. So you want to slowing adjust them in until it starts to stumble on just
the idle, then back them out 1/2 turn.

On the RB prepped Dell the AP has a thicker gasket and a slight bend in the
adjustment rod. You want to play with this very carefully (or not at all if the idle
mixture seems to fix it good enough). You adjust the AP by truning the small
nut on the rod. I think out gives you a large squirt and in lessens it. Anyway,
you can play with the AP to try to further minimize initial acceleration stumble.
Its all trial an error. Just remember to do one thing at a time.

Theres a good book called Tuning Weber and Dellorto carbs that really can
walk you thru all this. Also this site http://www.gruntled.com/Dellorto has a lot of
good info to help you out. It appears down right now but I'm sure it will pop
back. You can google it and look at it in googles cache as well.

 

thank you for your wisdom, i'll give it a shot tonight and see what happens.... OH!!!! i forgot to mention that this is on a 13b with high comp. rotors.... i don't know if that will effect the fuel psi any...


thanks

 

Nope psi still will be the same. You may need to invest in a few sets of jets to
get it right since its for a 13B. Check the gruntled site for details on the 13B.

 

ok so i adjusted the idle screws, it is better but still no good.... i have been looking online all night and morning and found everything i need to adjust the floats.... they are good and it is still screwed up... only other thing is the accelerator pump before i just rebuild the damn thing myself i guess....

i have looked at countless sights that tell me the ap needs to be adjusted to 13/32 of travel.... but this is useless to me because noone goes beyond that to tell you how to actually adjust this to achieve that movement and where to measure the movement from....

ANY ONE KNOW HOW TO ADJUST THIS THING?!?!??!?!?!??!!!!!

i am losing my mind!!!!!!! i spent way too much money, and all winter just for this to hold me back from driving it..... gimme just 10 minutes so i can at the very least have time to see how wonderful it is and break it again!!!!!!!!!!!!!

 

Was this a RB prepped Dellorto? If not then your going to have probems at the
transition because RB modded to the Del in various ways to work well with the
rotary.

What jets are you running? Have you compared those to what is listed on the gruntled site?

 

yep, all the jets are good for the 13b... the guy told me it was a racing beat prepped carb when i bought it, the only jet that i am not sure about is the ap jet which i am to afraid to pull out just because i have been told not to unless i have fresh parts to reinstall....

even if it isn't an rb dellorto though, i can understand it may not work "as well" and have stumbling, but this is beyond stumbling.... it just quits when you hit the throttle

now i have a new issue.... it will run ok now for about 20 seconds and just kill over.... like the bowl isn't refilling after it burns up what is in there... but upon inspection the bowl is filled like it should be and fuel pressure etc. is how it should be.....

also forgot to mention.... my air fuel gauge just drops off to lean suddenly right before everything dies as well... so i know it's just starving itself for some reason...

 

If it were me I would order the full rebuild kit from here and pull it off and completely go thru it.
Sounds like you have crap floating around and clogging passages.

You could try running some gumout or seafoam thru it first, it may just clean it
out. Was this thing sitting with gas in it for any amount of time? That will gum
it up good sometimes.

 

i really can't say... due to my pure lazyness i think i am going to sea foam it 1st... then i'll rebuild it lol

 

well after a little ghetto rebuild on the carb (sprayed out the jets with carb cleaner) it is yet one step closer to running like a normal rx7..... now it seems like at times it only wants to fuel one rotor.... but it isn't dying..... still stumbles and all that nonsense though..... tomorrow i'm gonna sea foam it and see how that goes.... i have a rebuild kit coming so when that gets here ill rebuild it myself so i know for sure its all in good order.... i'm just too impatient to wait.... after a long lonely winter without my 7 i NEEEEEEEEEEEEED HER!!!!!!!!!!!!!!!!

 

IT'S ALIIIIIIIIIIIVE!!!!!!!!!!!!!!!!!!!! took the rx7 for her 1st drive.... anything less than full throttle is absolutely horrible, but full throttle is AWESOMENESS!!!!! the car is horribly loud my ears are still ringing.... the engine starts blowing the spark out at around 7k so i'm gonna have to wire up the direct coil ignition to be able to get her up to 8k..... carb rebuild, finishing up the exhaust, and some ignition work and she will be an unstoppable little monster of a 1st gen!!!!!!!

THANK YOU SEA FOAM FOR LETTING ME DRIVE MY CAR!!!!!!!!! even if it was only for 5 minutes all year....

it is running retarded rich as well, when i parked the car i looked down below for leaks and my beautiful new RB presilencer was ON FIRE!!!!!! oh well, after the rebuild i am pretty sure all will be good